CMake improvements and cleanups

Add missing "-msse" flag, clean up old BUILD_SHARED flags (cmake has its own
system for doing this) and add a couple more build targets.
Add readme file for cmake building.

This adds a simple readme file for building the cmake project.
It includes the most common flags and quick build/install commands.
Resampler now adds input delay and subtracts output delay according to whichever quality is selected, rather than being fixed for sinc only. This fixes blep synthesis mode defeating note on and off volume ramping.
MSVC fix again
Merge pull request #4 from katajakasa/ttv-cmake-improvements

CMake readme+improvements
Updated sinc resampler with unscaled windowing, which fixes a lot of the previous aliasing
Attempt to fix issue #5 with compiling cpuid inline assembly on any platform using PIC
Don't include the MSVC debug header if we aren't using MSVC
Merge pull request #6 from Vagabond/adt-unix-debug

Don't include the MSVC debug header if we aren't using MSVC
Updated license from the original project with clause 8
Adjusted tempo timing a bit, now rounding samples per tick down instead of up